 /*******************************************************************************
  * Copyright (c) 2006, 2007 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.ui.texteditor.rulers;

 import java.util.Set ;

 import org.eclipse.core.runtime.Assert;

 import org.eclipse.jface.preference.IPreferenceStore;
 import org.eclipse.ui.internal.texteditor.rulers.StringSetSerializer;

 /**
  * Manages the preferences for ruler contributions stored in a preference store.
  *
  * @since 3.3
  */
 public final class RulerColumnPreferenceAdapter {
     private final IPreferenceStore fStore;
     private final String fKey;

     /**
      * Creates a new preference adapter that will read and write under the specified key in the
      * given preference store.
      *
      * @param store the preference store
      * @param key the key
      */
     public RulerColumnPreferenceAdapter(IPreferenceStore store, String key) {
         Assert.isLegal(store != null);
         Assert.isLegal(key != null);
         fStore= store;
         fKey= key;
     }
     
     /**
      * Returns the enablement state of the given ruler contribution.
      *
      * @param descriptor a ruler contribution descriptor
      * @return <code>true</code> if the ruler is enabled, <code>false</code> otherwise
      */
     public boolean isEnabled(RulerColumnDescriptor descriptor) {
         Assert.isLegal(descriptor != null);
         String preference= fStore.getString(fKey);
         return StringSetSerializer.deserialize(preference).contains(descriptor.getId()) ^ descriptor.getDefaultEnablement();
     }
     
     /**
      * Sets the enablement state of the given ruler contribution.
      *
      * @param descriptor a ruler contribution descriptor
      * @param enabled <code>true</code> to enable the contribution, <code>false</code> to
      * disable it
      */
     public void setEnabled(RulerColumnDescriptor descriptor, boolean enabled) {
         Assert.isLegal(descriptor != null);
         String id= descriptor.getId();
         String preference= fStore.getString(fKey);
         Set marked= StringSetSerializer.deserialize(preference);
         boolean shouldMark= enabled ^ descriptor.getDefaultEnablement();
         boolean isMarked= marked.contains(id);
         if (isMarked != shouldMark) {
             if (shouldMark)
                 marked.add(id);
             else
                 marked.remove(id);
             fStore.setValue(fKey, StringSetSerializer.serialize(marked));
         }
     }
     
     /**
      * Toggles the enablement state of given the ruler contribution.
      *
      * @param descriptor a ruler contribution descriptor
      */
     public void toggle(RulerColumnDescriptor descriptor) {
         Assert.isLegal(descriptor != null);
         setEnabled(descriptor, !isEnabled(descriptor));
     }
 }

